Monarch butterflies during winter?

Published 9:20 am, Friday, January 6, 2012

Photo Caption: This is one of a dozen winter monarch butterflies that were raised from larvae found by Bob Pish shortly before Christmas. Photograph by Bob Pish.

During the 12 years this column has been around, readers have sent hundreds of e-mails and letters about their discoveries and observations. One of the most interesting of these many notes arrived recently from reader Bob Pish.

On December 19, Bob wrote, “A week or two ago when we had the cold snap a butterfly weed [milkweed] plant died back and its leaves turned black. As I went to cut it back, I noticed a couple of caterpillars still on the plant. Assuming they would not make it through the cold, and that the odds of them continuing the migration were slim, I decided to make a little experiment that might save them and show me some new things.”

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Bob's e-mail included photographs that clearly showed monarch butterfly larvae. Since the monarch migration through Texas is ordinarily completed during November, finding stray monarchs in late December was quite unusual.

But finding monarch caterpillars in December was especially puzzling. Everything I've read about these fascinating creatures explains how monarchs that migrate to Mexico do not deposit eggs on milkweed plants during their fall migration to Mexico. Instead, the females deposit eggs on milkweeds during their return to Texas each spring. They then die, and their offspring continue flying north while producing new generations.

Eventually, the fourth or fifth generation of these insects emerges from tiny eggs in Canada or the Northeast US and matures into the especially sturdy monarchs that fly all the way back to Mexico during fall.

Bob collected a dozen winter monarch larvae and placed them in a temporary “Monarch House” along with some butterfly plants. He accompanied a series of detailed reports he sent with beautiful photographs of his monarch caterpillars and the chrysalises they formed in preparation for becoming butterflies.

The day before Christmas Eve, the first monarch emerged from its chrysalis and began expanding its wings. Bob's granddaughter Paige explained this process to him. On Christmas Eve, the butterfly made its first brief flight to a milkweed leaf. Bob's granddaughter Sophie named it Butter.

By now you might be wondering what will become of Bob Pish's winter monarch flock. He's notified Monarch Watch at the University of Kansas. Now he's wondering if he should release them on a warm winter day or offer them to a sheltered botanical garden.

You can keep up with this winter monarch adventure online. Bob Pish's story was so remarkable that I suggested he send his reports to the blog of the Citizen Scientists League at http://citizenscientistsleague.com. There you can read his reports, see his photos and find out what eventually happens to Butter and its siblings.

Forrest Mims, an amateur scientist whose research has appeared in leading scientific journals, was named one of the “50 Best Brains in Science” by Discover Magazine. His science is featured at www.forrestmims.org. E-mail him at forrest.mims@ieee.org.